Inspection After Surface Preparation

The surface appearance of the steel after blast cleaning is referred to in the Pictorial Standards. The ISO -1 standard (Swedish Rust Standard) identifies the appearance using grades of cleanliness together with reference pictures.

View Details

As with the rust grades discussed earlier, there are four grades of cleanliness for abrasive blast cleaning of new steel, these are as follows for A Grade steel:

The specification for the coating will detail which grade of cleanliness is required. To assess the cleaned surface, it should be compared to the appropriate photographs in the Standard. Beware, these Standards are often referred to as 'Profile Standards' but this is not the case. Instead, they are Surface Cleanliness Standards - the two are commonly confused.

Note: For different grades of steel (B, C and D steels), there are different cleanliness grades (SB, SC and SD). These are also referred to in the ISO -1 Standard with the relevant photographs. There are also different cleanliness grades for flame-cleaned and water-cleaned substrates.

Flame cleaning is the process of cleaning a structural steel surface by passing a very hot oxyacetylene flame over it. An oxygen-fuelled torch is used parallel with the surface to melt and blow off any blemishes that the operator wants to, including some of the hardest to clean substances such as lubricants and grease. There are also visual cleanliness Standards available for other substrate types such as concrete.

If you are looking for more details, kindly visit Eastloong.

Please note there are several versions of Pictorial Standards and the choice of which standardise used is stated in the job specification. Below is a list of those most frequently used: 

• ISO -1 (Swedish Rust Standard)
• SSPC VIS 1-01 (SSPC equivalent to Swedish Rust Standard)
• SSPC VIS-2 (Degree of rusting on painted surfaces)
• SSPC VIS-3 (Hand and Power Tools)
• SSPC VIS-4 (Water jetting)
• SSPC VIS-5 (Wet abrasive)
• BS EN ISO -4 (High pressure water jetting)
• ASTM D -08 Standard Practice for Use of Pictorial Surface Preparation Standards and Guides for Painting Steel Surfaces
• IMO MSC 215(82)
• IMO MSC 244(83)
• US Navy NSI 009-32
• US Navy PPI -000

As well as a visual inspection to assess the cleanliness of a surface (using Pictorial Standards), it is possible to measure/assess the surface profile achieved during the blasting operation and to test the surface of the substrate for non-visible contaminants such as chloride, sulphate or nitrate ions. These methods are discussed in the sections to follow.

The level of &#;acceptability&#; is usually defined within the specifications of the contract and can also be determined by the coating&#;s material data sheet.

You have questions. We have answers. 

Our Steel Solutions Center staff answer hundreds of questions each week. We answer technical questions on structural steel design and can help you understand AISC's technical publications. Additionally, we strive to answer questions within 24 hours. 

Have questions on any of our Technical Resources? Feel free to ask us about them! Have questions on structural steel design? Go ahead and ask us! We have answers and they are free and easy to obtain. 

Check out our Engineering FAQs below or contact our Steel Solutions Center now! 

If you want to learn more, please visit our website Surface Inspection System For Steel.